The picture of Phelps smoking from a marijuana pipe was published in the News of the World shortly after he signed a seven-figure deal to represent Mazda in China.
In the Phelps said the past few days had been tough, but "the warmth and forgiveness" he had received from his Chinese fans had made his life easier.
Speaking of the bong revelations he said: "To the young people of China please learn from this lesson, be positive in life and do the right thing."
Since the revelations appeared there has been a mixed reaction from Phelps' sponsors.
Omega, Visa, Subway and Speedo announced they would stand by the star while Kellogg's parted company with him saying his behaviour was not consistent with its values.
In Los Angeles the fallout from the episode continues as eight people with connections to the party where Phelps smoked the pipe have been arrested.
There have also been reports that the bong's owner has been trying to sell it on eBay for $100,000 (£69,000).
Someone is also trying to sell the domain name on the online auction site for $9,500 (£6,600).